CHANGELOG.md

@@ -23,6 +23,63 @@ skip versions are the composition of each intervening adjacent
 release's steps in order — no A-to-B path is pre-computed beyond
 that.
 
+## 0.41.0 — 2026-06-05
+
+**Minor (non-breaking) — §22 three-tier refactor, slice S2: *create & navigate a
+second collection.* A deployment can now host more than one RFC collection per
+project: a second collection is created, navigated, and proposed into beside the
+default one. Purely additive — a single-collection deployment is unchanged (its
+`/p/<project>/` still redirects into the sole collection, C3.7/C3.8). Completes
+acceptance scenario `@S2` (C3.6: an anonymous reader of an empty public
+collection sees an empty catalog with no propose action and a sign-in prompt).**
+
+See [`docs/design/2026-06-05-three-tier-projects-collections.md`](./docs/design/2026-06-05-three-tier-projects-collections.md)
+(Part E slice S2) and the slice plan
+[`docs/design/plans/2026-06-05-s2-second-collection.md`](./docs/design/plans/2026-06-05-s2-second-collection.md).
+Scoped {owner, contributor} roles at the collection axis remain S3; the
+role-keyed create/propose-first empty states remain S4.
+
+Added:
+
+- **Named collections via `.collection.yaml`** — the registry mirror walks each
+  project's content repo and upserts a collection per
+  `<subfolder>/.collection.yaml` manifest (`type`, optional `visibility` /
+  `initial_state` / `name`; `type` immutable per §22.4a, visibility inherits the
+  project's when omitted). The default collection still flows from
+  `projects.yaml`.
+- **create-collection** — `POST /api/projects/<id>/collections` (deployment
+  owner/admin). The bot commits a `.collection.yaml` to the content repo's
+  `main`, then the registry re-mirrors so the `collections` row appears (the
+  registry stays the source of truth, §22.2). New reads
+  `GET /api/projects/<id>/collections` and `…/collections/<cid>`.
+- **Collection-scoped serve + propose** —
+  `GET /api/projects/<id>/collections/<cid>/rfcs[/<slug>]` and
+  `POST …/collections/<cid>/rfcs/propose`. A propose writes the entry under the
+  target collection's `<subfolder>/rfcs/`.
+- **Collection directory at `/p/<project>/`** — lists the project's visible
+  collections, or redirects into the sole one when there is exactly one
+  (preserving the S1 single-collection UX). The catalog rail + entry views read
+  the active `/c/<collection>/` segment and scope to it.
+
+Changed:
+
+- **The corpus mirror is collection-grained** — `cache.refresh_meta_repo`
+  iterates each project's collections and reads each collection's
+  `<subfolder>/rfcs/`, keying `cached_rfcs` by `collection_id`. The default
+  collection keeps the shipped repo-root `rfcs/` path; N=1 serving is unchanged.
+
+> ### Upgrade steps (0.40.0 → 0.41.0)
+>
+> - No required operator action — the slice is additive and the default-collection
+>   paths are unchanged. A deployment **MAY** deploy this version with no config
+>   change and keep running exactly as on 0.40.0.
+> - To add a second collection, a deployment owner/admin **MAY** call
+>   `POST /api/projects/<id>/collections` (or commit a `<subfolder>/.collection.yaml`
+>   to the content repo directly); the registry mirror picks it up on the next
+>   refresh.
+> - Deployments that pin the framework version **MUST** bump their version pin to
+>   `0.41.0`.
+
 ## 0.40.0 — 2026-06-05
 
 **Minor (breaking URL) — §22 three-tier refactor, slice S1: the *collection*

VERSION

@@ -1 +1 @@
-0.40.0
+0.41.0

backend/app/api.py

@@ -21,6 +21,7 @@ from pydantic import BaseModel, Field
 from . import (
     api_admin,
     api_branches,
+    api_collections,
     api_contributions,
     api_deployment,
     api_discussion,
@@ -152,6 +153,7 @@ def make_router(
     # §22.9/§22.10 (M3): runtime deployment + per-project config (replaces
     # VITE_APP_NAME) + the old-URL 308 redirects.
     router.include_router(api_deployment.make_router(config))
+    router.include_router(api_collections.make_router(config, gitea, bot))
 
     # ---------------------------------------------------------------
     # §17: /api/health — unauthenticated post-flight probe.
@@ -717,15 +719,15 @@ def make_router(
     # second project's corpus renders under /p/<id>/.
     # ---------------------------------------------------------------
 
-    @router.get("/api/projects/{project_id}/rfcs")
-    async def list_project_rfcs(
-        project_id: str, request: Request, unreviewed: str | None = None
+    def _require_collection_in_project(collection_id: str, project_id: str) -> None:
+        # §22 S2: a collection-scoped route 404s when the collection does not
+        # belong to the project in the path (shape matches an unknown id).
+        if collections_mod.project_of_collection(collection_id) != project_id:
+            raise HTTPException(404, "Not found")
+
+    def _list_rfcs_for_collection(
+        collection_id: str, viewer, unreviewed: str | None
     ) -> dict[str, Any]:
-        viewer = auth.current_user(request)
-        # §22.5 read gate: a gated project's catalog 404s to a non-member.
-        auth.require_project_readable(viewer, project_id)
-        # §22 S1: serve the project's default collection (the corpus grain).
-        collection_id = collections_mod.default_collection_id(project_id)
         viewer_id = viewer.user_id if viewer else None
         unreviewed_clause = ""
         if unreviewed is not None and unreviewed.lower() in ("1", "true", "yes"):
@@ -769,11 +771,7 @@ def make_router(
         ]
         return {"items": items}
 
-    @router.get("/api/projects/{project_id}/rfcs/{slug}")
-    async def get_project_rfc(project_id: str, slug: str, request: Request) -> dict[str, Any]:
-        viewer = auth.current_user(request)
-        auth.require_project_readable(viewer, project_id)
-        collection_id = collections_mod.default_collection_id(project_id)
+    def _get_rfc_for_collection(collection_id: str, slug: str, viewer) -> dict[str, Any]:
         row = db.conn().execute(
             "SELECT * FROM cached_rfcs WHERE collection_id = ? AND slug = ?",
             (collection_id, slug),
@@ -794,6 +792,46 @@ def make_router(
         payload["proposed_use_case"] = uc["use_case"] if uc else None
         return payload
 
+    @router.get("/api/projects/{project_id}/rfcs")
+    async def list_project_rfcs(
+        project_id: str, request: Request, unreviewed: str | None = None
+    ) -> dict[str, Any]:
+        viewer = auth.current_user(request)
+        # §22.5 read gate: a gated project's catalog 404s to a non-member.
+        auth.require_project_readable(viewer, project_id)
+        # §22 S1: the project-scoped route serves the default collection.
+        collection_id = collections_mod.default_collection_id(project_id)
+        return _list_rfcs_for_collection(collection_id, viewer, unreviewed)
+
+    @router.get("/api/projects/{project_id}/rfcs/{slug}")
+    async def get_project_rfc(project_id: str, slug: str, request: Request) -> dict[str, Any]:
+        viewer = auth.current_user(request)
+        auth.require_project_readable(viewer, project_id)
+        collection_id = collections_mod.default_collection_id(project_id)
+        return _get_rfc_for_collection(collection_id, slug, viewer)
+
+    # §22 S2: collection-scoped serve + propose. The catalog/entry views read
+    # these under /p/<project>/c/<collection>/; the project-scoped routes above
+    # stay as the default-collection compat surface.
+    @router.get("/api/projects/{project_id}/collections/{collection_id}/rfcs")
+    async def list_collection_rfcs(
+        project_id: str, collection_id: str, request: Request,
+        unreviewed: str | None = None,
+    ) -> dict[str, Any]:
+        viewer = auth.current_user(request)
+        auth.require_project_readable(viewer, project_id)
+        _require_collection_in_project(collection_id, project_id)
+        return _list_rfcs_for_collection(collection_id, viewer, unreviewed)
+
+    @router.get("/api/projects/{project_id}/collections/{collection_id}/rfcs/{slug}")
+    async def get_collection_rfc(
+        project_id: str, collection_id: str, slug: str, request: Request
+    ) -> dict[str, Any]:
+        viewer = auth.current_user(request)
+        auth.require_project_readable(viewer, project_id)
+        _require_collection_in_project(collection_id, project_id)
+        return _get_rfc_for_collection(collection_id, slug, viewer)
+
     # ---------------------------------------------------------------
     # §22.4c: mark-reviewed — clear an active entry's `unreviewed` flag
     # ---------------------------------------------------------------
@@ -957,6 +995,15 @@ def make_router(
     # ---------------------------------------------------------------
 
     async def _propose_into_project(project_id: str, payload: ProposeBody, user) -> dict[str, Any]:
+        # Default-collection wrapper (§22 S1/S2): resolve the project's default
+        # collection and delegate. Keeps the project-scoped propose routes intact.
+        return await _propose_into_collection(
+            project_id, collections_mod.default_collection_id(project_id), payload, user
+        )
+
+    async def _propose_into_collection(
+        project_id: str, collection_id: str, payload: ProposeBody, user
+    ) -> dict[str, Any]:
         # §22.6/§22.7: proposing a new entry requires project-level contribute
         # standing in the *target* project. On the public default project the
         # implicit-public baseline preserves the pre-multi-project flow.
@@ -970,7 +1017,6 @@ def make_router(
         # We re-check atomically here even though the client also checks
         # on every keystroke, since a concurrent submission could land
         # between dialog-open and submit.
-        collection_id = collections_mod.default_collection_id(project_id)
         clash = db.conn().execute(
             "SELECT 1 FROM cached_rfcs WHERE slug = ? AND collection_id = ?", (slug, collection_id)
         ).fetchone()
@@ -984,11 +1030,12 @@ def make_router(
         if idea_clash:
             raise HTTPException(409, f"Slug `{slug}` is already reserved by an open proposal")
 
-        # §22.4b: the target project's landing state. Through Plan A every
-        # entry lands in the default project; M3-frontend routing carries a
-        # non-default target later.
-        target_project = project_id
-        landing_state = "active" if projects_mod.project_initial_state(target_project) == "active" else "super-draft"
+        # §22.4b: the target collection's landing state (the per-corpus field
+        # moved down to the collection in migration 029).
+        landing_state = (
+            "active" if collections_mod.collection_initial_state(collection_id) == "active"
+            else "super-draft"
+        )
 
         entry = entry_mod.Entry(
             slug=slug,
@@ -1019,6 +1066,9 @@ def make_router(
             f"**Topic:** {entry.title}\n\n"
             f"{payload.pitch.strip()}"
         )
+        # §22 S2: write the entry under the target collection's <subfolder>/rfcs.
+        subfolder = collections_mod.subfolder_of(collection_id)
+        rfcs_dir = f"{subfolder}/rfcs" if subfolder else "rfcs"
         try:
             pr = await bot.open_idea_pr(
                 user.as_actor(),
@@ -1028,6 +1078,7 @@ def make_router(
                 file_contents=contents,
                 pr_title=pr_title,
                 pr_description=pr_description,
+                rfcs_dir=rfcs_dir,
             )
         except GiteaError as e:
             raise HTTPException(502, f"Gitea: {e.detail}")
@@ -1076,6 +1127,16 @@ def make_router(
         auth.require_project_readable(user, project_id)
         return await _propose_into_project(project_id, payload, user)
 
+    @router.post("/api/projects/{project_id}/collections/{collection_id}/rfcs/propose")
+    async def propose_collection_rfc(
+        project_id: str, collection_id: str, payload: ProposeBody, request: Request
+    ) -> dict[str, Any]:
+        # §22 S2: propose a new entry into a specific collection of a project.
+        user = auth.require_contributor(request)
+        auth.require_project_readable(user, project_id)
+        _require_collection_in_project(collection_id, project_id)
+        return await _propose_into_collection(project_id, collection_id, payload, user)
+
     # ---------------------------------------------------------------
     # §9.1 Slice 2 (roadmap #27): Claude Haiku tag suggestions as the
     # propose-RFC fields fill in. The modal debounce-posts the partial

backend/app/api_collections.py

@@ -0,0 +1,112 @@
+"""§22 S2 — collection directory + create-collection.
+
+GET  /api/projects/:id/collections        — list the project's visible collections.
+GET  /api/projects/:id/collections/:cid    — one collection's settings.
+POST /api/projects/:id/collections         — create a collection. Authorized by a
+                                             deployment owner/admin (S2; scoped
+                                             {owner, contributor} roles at the
+                                             collection axis land in S3). The bot
+                                             commits a `.collection.yaml` to the
+                                             content repo, then the registry mirror
+                                             upserts the collections row — §22.2
+                                             keeps the registry the source of truth.
+"""
+from __future__ import annotations
+
+import re
+from typing import Any
+
+import yaml
+from fastapi import APIRouter, HTTPException, Request
+from pydantic import BaseModel
+
+from . import (
+    auth,
+    collections as collections_mod,
+    projects as projects_mod,
+    registry as registry_mod,
+)
+from .bot import Bot
+from .config import Config
+from .gitea import Gitea, GiteaError
+
+_SLUG_RE = re.compile(r"^[a-z0-9](?:[a-z0-9-]*[a-z0-9])?$")
+
+
+class CreateCollectionBody(BaseModel):
+    collection_id: str
+    type: str
+    name: str | None = None
+    visibility: str | None = None
+    initial_state: str | None = None
+
+
+def make_router(config: Config, gitea: Gitea, bot: Bot) -> APIRouter:
+    router = APIRouter()
+
+    @router.get("/api/projects/{project_id}/collections")
+    async def list_cols(project_id: str, request: Request) -> dict[str, Any]:
+        viewer = auth.current_user(request)
+        # §22.5 read gate: a gated project 404s a non-member.
+        auth.require_project_readable(viewer, project_id)
+        return {"items": collections_mod.list_collections(project_id)}
+
+    @router.get("/api/projects/{project_id}/collections/{collection_id}")
+    async def get_col(project_id: str, collection_id: str, request: Request) -> dict[str, Any]:
+        viewer = auth.current_user(request)
+        auth.require_project_readable(viewer, project_id)
+        col = collections_mod.get_collection(collection_id)
+        if col is None or col["project_id"] != project_id:
+            raise HTTPException(404, "Not found")
+        return col
+
+    @router.post("/api/projects/{project_id}/collections")
+    async def create_col(
+        project_id: str, body: CreateCollectionBody, request: Request
+    ) -> dict[str, Any]:
+        # S2 authority: deployment owner/admin (the scoped-role surface is S3).
+        user = auth.require_admin(request)
+        auth.require_project_readable(user, project_id)
+        cid = body.collection_id.strip().lower()
+        if not _SLUG_RE.match(cid) or cid == "default":
+            raise HTTPException(422, "collection id must be a slug and not 'default'")
+        if body.type not in registry_mod.VALID_TYPES:
+            raise HTTPException(422, f"invalid type {body.type!r}")
+        if body.visibility is not None and body.visibility not in registry_mod.VALID_VISIBILITY:
+            raise HTTPException(422, f"invalid visibility {body.visibility!r}")
+        if body.initial_state is not None and body.initial_state not in registry_mod.VALID_INITIAL_STATE:
+            raise HTTPException(422, f"invalid initial_state {body.initial_state!r}")
+        if collections_mod.get_collection(cid) is not None:
+            raise HTTPException(409, f"collection `{cid}` already exists")
+        content_repo = projects_mod.content_repo(project_id)
+        if not content_repo:
+            raise HTTPException(409, "project has no content repo")
+
+        manifest: dict[str, Any] = {"type": body.type}
+        if body.name:
+            manifest["name"] = body.name
+        if body.visibility:
+            manifest["visibility"] = body.visibility
+        if body.initial_state:
+            manifest["initial_state"] = body.initial_state
+        manifest_yaml = yaml.safe_dump(manifest, sort_keys=False)
+
+        try:
+            await bot.create_collection(
+                user.as_actor(),
+                org=config.gitea_org,
+                content_repo=content_repo,
+                collection_id=cid,
+                manifest_yaml=manifest_yaml,
+            )
+        except GiteaError as e:
+            raise HTTPException(502, f"Gitea: {e.detail}")
+
+        # §22.2: re-read the registry so the new manifest becomes a row.
+        await registry_mod.refresh_registry(config, gitea)
+        col = collections_mod.get_collection(cid)
+        if col is None:
+            raise HTTPException(500, "collection committed but not mirrored")
+        return col
+
+    return router

backend/app/bot.py

@@ -163,6 +163,41 @@ class Bot:
     def __init__(self, gitea: Gitea):
         self._gitea = gitea
 
+    # ----- Content repo: collection structure (§22 S2) -----
+
+    async def create_collection(
+        self,
+        actor: Actor,
+        *,
+        org: str,
+        content_repo: str,
+        collection_id: str,
+        manifest_yaml: str,
+    ) -> dict:
+        """§22 S2: commit `<collection_id>/.collection.yaml` to the content
+        repo's main. A structural admin action — committed straight to main (no
+        PR), like the registry config it feeds; the registry mirror then upserts
+        the collections row (§22.2 keeps the registry the source of truth). Logs
+        an audit row for the §6.5 trail."""
+        path = f"{collection_id}/.collection.yaml"
+        created = await self._gitea.create_file(
+            org,
+            content_repo,
+            path,
+            content=manifest_yaml,
+            message=_stamp_single(f"chore: create collection {collection_id}", actor),
+            branch="main",
+            author_name=actor.display_name,
+            author_email=actor.email or f"{actor.gitea_login}@users.noreply",
+        )
+        _log(
+            actor,
+            "create_collection",
+            bot_commit_sha=created.get("commit", {}).get("sha"),
+            details={"collection_id": collection_id, "repo": content_repo},
+        )
+        return created
+
     # ----- Meta repo: idea PRs (§9.1 / §9.2) -----
 
     async def open_idea_pr(
@@ -175,12 +210,16 @@ class Bot:
         file_contents: str,
         pr_title: str,
         pr_description: str,
+        rfcs_dir: str = "rfcs",
     ) -> dict:
-        """Per §9.1: open a meta-repo PR adding one file under rfcs/.
+        """Per §9.1: open a meta-repo PR adding one file under `<rfcs_dir>/`.
 
         One file per PR keeps idea submissions atomic and conflict-free.
         The PR title and the file-add commit subject share §9.2's fixed
-        pattern; callers compose `pr_title` as `Propose: <Title>`.
+        pattern; callers compose `pr_title` as `Propose: <Title>`. §22 S2:
+        `rfcs_dir` carries the target collection's `<subfolder>/rfcs` so a
+        propose into a named collection writes under its subfolder; it
+        defaults to `rfcs` (the default collection / shipped behaviour).
         """
         branch = f"propose/{slug}"
         await self._gitea.create_branch(org, meta_repo, branch, from_branch="main")
@@ -189,7 +228,7 @@ class Bot:
         created = await self._gitea.create_file(
             org,
             meta_repo,
-            f"rfcs/{slug}.md",
+            f"{rfcs_dir}/{slug}.md",
             content=file_contents,
             message=commit_message,
             branch=branch,

backend/app/cache.py

@@ -54,15 +54,27 @@ async def refresh_meta_repo(config: Config, gitea: Gitea) -> None:
 
 
 async def _refresh_project_corpus(org: str, project_id: str, repo: str, gitea: Gitea) -> None:
-    # §22 S1: the corpus grain is the collection. The mirror is project-grained
-    # (reads rfcs/ at the repo root = the project's default collection); resolve
-    # that collection once and key cached_rfcs by it.
+    # §22 S2: the corpus grain is the collection. Mirror every collection of the
+    # project from its `<subfolder>/rfcs/` directory, keying cached_rfcs by the
+    # collection id. The default collection (subfolder '') reads `rfcs/` — the
+    # shipped path, unchanged. include_unlisted: the mirror serves every
+    # collection's content regardless of enumeration visibility.
     from . import collections as collections_mod
-    collection_id = collections_mod.default_collection_id(project_id)
+    for col in collections_mod.list_collections(project_id, include_unlisted=True):
+        await _refresh_collection_corpus(
+            org, project_id, repo, col["id"], col["subfolder"] or "", gitea
+        )
+
+
+async def _refresh_collection_corpus(
+    org: str, project_id: str, repo: str, collection_id: str, subfolder: str, gitea: Gitea
+) -> None:
+    rfcs_dir = f"{subfolder}/rfcs" if subfolder else "rfcs"
     try:
-        files = await gitea.list_dir(org, repo, "rfcs", ref="main")
+        files = await gitea.list_dir(org, repo, rfcs_dir, ref="main")
     except GiteaError as e:
-        log.warning("refresh_meta_repo: project %s: cannot list rfcs/: %s", project_id, e)
+        log.warning("refresh_meta_repo: %s/%s: cannot list %s: %s",
+                    project_id, collection_id, rfcs_dir, e)
         return
 
     seen_slugs: set[str] = set()
@@ -76,17 +88,19 @@ async def _refresh_project_corpus(org: str, project_id: str, repo: str, gitea: G
         try:
             entry = entry_mod.parse(text)
         except Exception as parse_err:
-            log.warning("refresh_meta_repo: %s: skipping %s: %s", project_id, f["path"], parse_err)
+            log.warning("refresh_meta_repo: %s/%s: skipping %s: %s",
+                        project_id, collection_id, f["path"], parse_err)
             continue
         if not entry.slug:
-            log.warning("refresh_meta_repo: %s: skipping %s: missing slug", project_id, f["path"])
+            log.warning("refresh_meta_repo: %s/%s: skipping %s: missing slug",
+                        project_id, collection_id, f["path"])
             continue
         seen_slugs.add(entry.slug)
         _upsert_cached_rfc(entry, body_sha=sha, collection_id=collection_id)
 
-    # Entries removed from a project's rfcs/ — the spec keeps withdrawn entries
+    # Entries removed from a collection's rfcs/ — the spec keeps withdrawn entries
     # as historical record (§3), so this fires only for out-of-band deletes;
-    # leave the row, scoped to this project, for reconciler attention.
+    # leave the row, scoped to this collection, for reconciler attention.
     existing = {
         row["slug"]
         for row in db.conn().execute(
@@ -94,7 +108,8 @@ async def _refresh_project_corpus(org: str, project_id: str, repo: str, gitea: G
         )
     }
     for missing in existing - seen_slugs:
-        log.info("refresh_meta_repo: %s/%s no longer in rfcs/ — leaving cache row", project_id, missing)
+        log.info("refresh_meta_repo: %s/%s/%s no longer present — leaving cache row",
+                 project_id, collection_id, missing)
 
 
 def _upsert_cached_rfc(entry: entry_mod.Entry, body_sha: str, collection_id: str = "default") -> None:

backend/app/collections.py

@@ -48,3 +48,39 @@ def collection_type(collection_id: str) -> str:
         "SELECT type FROM collections WHERE id = ?", (collection_id,)
     ).fetchone()
     return row["type"] if row and row["type"] else "document"
+
+
+def subfolder_of(collection_id: str) -> str:
+    """The content-repo subfolder a collection lives under (§22.3). Empty string
+    for the default collection (entries at the repo root `rfcs/`)."""
+    row = db.conn().execute(
+        "SELECT subfolder FROM collections WHERE id = ?", (collection_id,)
+    ).fetchone()
+    return (row["subfolder"] if row else "") or ""
+
+
+def get_collection(collection_id: str) -> dict | None:
+    """The full collection row as a dict, or None if unknown."""
+    row = db.conn().execute(
+        "SELECT id, project_id, type, subfolder, initial_state, visibility, name "
+        "FROM collections WHERE id = ?",
+        (collection_id,),
+    ).fetchone()
+    return dict(row) if row else None
+
+
+def list_collections(project_id: str, include_unlisted: bool = False) -> list[dict]:
+    """Collections in a project, the default first then by name (§22.5). `unlisted`
+    is omitted from enumeration unless include_unlisted (a direct-id read or the
+    corpus mirror, which serves every collection)."""
+    rows = db.conn().execute(
+        "SELECT id, project_id, type, subfolder, initial_state, visibility, name "
+        "FROM collections WHERE project_id = ? ORDER BY (id != 'default'), name, id",
+        (project_id,),
+    ).fetchall()
+    out: list[dict] = []
+    for r in rows:
+        if not include_unlisted and r["visibility"] == "unlisted":
+            continue
+        out.append(dict(r))
+    return out

backend/app/registry.py

@@ -55,6 +55,17 @@ class ProjectEntry:
     config: dict = field(default_factory=dict)  # theme, enabled_models
 
 
+@dataclass
+class CollectionEntry:
+    """A named collection declared by a `.collection.yaml` manifest inside a
+    project's content repo (S2). `visibility=None` means "inherit the project's
+    visibility"."""
+    type: str
+    visibility: str | None
+    initial_state: str
+    name: str | None
+
+
 @dataclass
 class RegistryDoc:
     deployment_name: str
@@ -114,6 +125,33 @@ def parse_registry(text: str) -> RegistryDoc:
     )
 
 
+def parse_collection_manifest(text: str) -> CollectionEntry:
+    """Parse + validate a `.collection.yaml`. Pure (no I/O). Raises RegistryError.
+
+    `type` is required and immutable (§22.4a, enforced at upsert). `visibility`
+    is optional — omitted means inherit the project's. `initial_state` defaults
+    per type (§22.4b)."""
+    raw = yaml.safe_load(text) or {}
+    if not isinstance(raw, dict):
+        raise RegistryError("collection manifest must be a mapping")
+    ctype = str(raw.get("type") or "").strip()
+    if ctype not in VALID_TYPES:
+        raise RegistryError(f"collection has invalid type {ctype!r}")
+    vis = raw.get("visibility")
+    if vis is not None:
+        vis = str(vis).strip()
+        if vis not in VALID_VISIBILITY:
+            raise RegistryError(f"collection has invalid visibility {vis!r}")
+    initial_state = str(
+        raw.get("initial_state") or _TYPE_DEFAULT_INITIAL_STATE[ctype]
+    ).strip()
+    if initial_state not in VALID_INITIAL_STATE:
+        raise RegistryError(f"collection has invalid initial_state {initial_state!r}")
+    name = raw.get("name")
+    name = str(name).strip() if name else None
+    return CollectionEntry(ctype, vis, initial_state, name)
+
+
 def _default_collection_id(project_id: str, default_id: str) -> str:
     """The id of a project's default collection. The deployment's primary
     project (== `default_id`, the §22.13 resolved default) gets the stable
@@ -193,6 +231,71 @@ def apply_registry(doc: RegistryDoc, registry_sha: str, default_id: str) -> None
         )
 
 
+def _upsert_named_collection(
+    proj: ProjectEntry, subdir: str, ce: CollectionEntry, sha: str
+) -> None:
+    """Upsert one named collection (S2). Type is immutable (§22.4a): a type
+    change against an existing row is refused (logged, not applied). A None
+    manifest visibility inherits the project's visibility."""
+    visibility = ce.visibility or proj.visibility
+    with db.tx() as conn:
+        existing = conn.execute(
+            "SELECT type FROM collections WHERE id = ?", (subdir,)
+        ).fetchone()
+        if existing is not None and existing["type"] != ce.type:
+            log.error(
+                "registry: refusing immutable type change on collection %s (%s -> %s)",
+                subdir, existing["type"], ce.type,
+            )
+            return
+        conn.execute(
+            """
+            INSERT INTO collections
+                (id, project_id, type, subfolder, initial_state, visibility, name, registry_sha, updated_at)
+            VALUES (?, ?, ?, ?, ?, ?, ?, ?, datetime('now'))
+            ON CONFLICT(id) DO UPDATE SET
+                project_id = excluded.project_id,
+                initial_state = excluded.initial_state,
+                visibility = excluded.visibility,
+                name = excluded.name,
+                registry_sha = excluded.registry_sha,
+                updated_at = datetime('now')
+            """,
+            (subdir, proj.id, ce.type, subdir, ce.initial_state, visibility, ce.name, sha),
+        )
+
+
+async def _mirror_named_collections(config: Config, gitea: Gitea, doc: RegistryDoc, sha: str) -> None:
+    """§22 S2: named collections are declared by `.collection.yaml` manifests
+    inside each project's content repo (the default collection comes from
+    projects.yaml). Walk each content repo root; a subdir carrying a manifest
+    becomes a collection keyed by the subdir name. Tolerant: a transport or
+    parse failure on one project/collection logs and is skipped, never aborts
+    the wider mirror (keep last-good)."""
+    for proj in doc.projects:
+        try:
+            items = await gitea.list_dir(config.gitea_org, proj.content_repo, "", ref="main")
+        except Exception as e:  # noqa: BLE001 — GiteaError/transport: tolerate
+            log.warning("registry: cannot list %s root: %s", proj.content_repo, e)
+            continue
+        for it in items:
+            if it.get("type") != "dir":
+                continue
+            subdir = it["name"]
+            manifest = await gitea.get_contents(
+                config.gitea_org, proj.content_repo, f"{subdir}/.collection.yaml", ref="main"
+            )
+            if not manifest or manifest.get("type") != "file":
+                continue
+            mtext = base64.b64decode(manifest["content"]).decode("utf-8")
+            try:
+                ce = parse_collection_manifest(mtext)
+            except RegistryError as e:
+                log.error("registry: bad manifest %s/%s: %s", proj.content_repo, subdir, e)
+                continue
+            _upsert_named_collection(proj, subdir, ce, sha)
+
+
 async def refresh_registry(config: Config, gitea: Gitea) -> None:
     """Mirror REGISTRY_REPO/projects.yaml into projects + deployment.
 
@@ -213,4 +316,6 @@ async def refresh_registry(config: Config, gitea: Gitea) -> None:
     doc = parse_registry(text)
     from . import projects as projects_mod
     apply_registry(doc, sha, projects_mod.resolved_default_id(config))
+    # §22 S2: discover + upsert named collections from each content repo.
+    await _mirror_named_collections(config, gitea, doc, sha)
     log.info("registry: mirrored %d project(s) at %s", len(doc.projects), sha)

backend/tests/test_collection_create_vertical.py

@@ -0,0 +1,83 @@
+"""§22 S2 — create-collection vertical: a deployment owner/admin POSTs, the bot
+commits a `.collection.yaml`, and the registry mirror upserts the collections
+row (registry stays the source of truth)."""
+from __future__ import annotations
+
+from fastapi.testclient import TestClient
+
+from app import db
+from test_propose_vertical import (  # noqa: F401
+    app_with_fake_gitea, tmp_env, provision_user_row, sign_in_as,
+)
+
+
+def test_create_collection_commits_manifest_and_mirrors(app_with_fake_gitea):
+    app, fake = app_with_fake_gitea
+    with TestClient(app) as client:
+        provision_user_row(user_id=1, login="ben", role="owner")
+        sign_in_as(client, user_id=1, gitea_login="ben", display_name="Ben",
+                   role="owner", email="ben@test")
+        r = client.post("/api/projects/default/collections",
+                        json={"collection_id": "features", "type": "bdd", "name": "Features"})
+        assert r.status_code == 200, r.text
+        assert r.json()["type"] == "bdd"
+
+        # The bot committed the manifest to the content repo's main.
+        f = fake.files.get(("wiggleverse", "meta", "main", "features/.collection.yaml"))
+        assert f is not None
+        assert "type: bdd" in f["content"]
+
+        # The registry refresh mirrored it into a collections row.
+        row = db.conn().execute(
+            "SELECT type, project_id, subfolder FROM collections WHERE id='features'"
+        ).fetchone()
+        assert (row["type"], row["project_id"], row["subfolder"]) == ("bdd", "default", "features")
+
+        # It is now navigable via the directory + scoped serve.
+        items = client.get("/api/projects/default/collections").json()["items"]
+        assert any(c["id"] == "features" for c in items)
+        assert client.get("/api/projects/default/collections/features/rfcs").status_code == 200
+
+
+def test_create_collection_requires_admin(app_with_fake_gitea):
+    app, _ = app_with_fake_gitea
+    with TestClient(app) as client:
+        provision_user_row(user_id=2, login="alice", role="contributor")
+        sign_in_as(client, user_id=2, gitea_login="alice", display_name="Alice",
+                   role="contributor", email="alice@test")
+        r = client.post("/api/projects/default/collections",
+                        json={"collection_id": "x", "type": "bdd"})
+        assert r.status_code in (401, 403)
+
+
+def test_create_collection_anonymous_rejected(app_with_fake_gitea):
+    app, _ = app_with_fake_gitea
+    with TestClient(app) as client:
+        r = client.post("/api/projects/default/collections",
+                        json={"collection_id": "x", "type": "bdd"})
+        assert r.status_code in (401, 403)
+
+
+def test_create_collection_rejects_duplicate(app_with_fake_gitea):
+    app, _ = app_with_fake_gitea
+    with TestClient(app) as client:
+        provision_user_row(user_id=1, login="ben", role="owner")
+        sign_in_as(client, user_id=1, gitea_login="ben", display_name="Ben",
+                   role="owner", email="ben@test")
+        ok = client.post("/api/projects/default/collections",
+                         json={"collection_id": "features", "type": "bdd"})
+        assert ok.status_code == 200, ok.text
+        dup = client.post("/api/projects/default/collections",
+                          json={"collection_id": "features", "type": "bdd"})
+        assert dup.status_code == 409
+
+
+def test_create_collection_rejects_reserved_default_id(app_with_fake_gitea):
+    app, _ = app_with_fake_gitea
+    with TestClient(app) as client:
+        provision_user_row(user_id=1, login="ben", role="owner")
+        sign_in_as(client, user_id=1, gitea_login="ben", display_name="Ben",
+                   role="owner", email="ben@test")
+        r = client.post("/api/projects/default/collections",
+                        json={"collection_id": "default", "type": "bdd"})
+        assert r.status_code == 422

backend/tests/test_collection_helpers.py

@@ -0,0 +1,64 @@
+"""§22 S2 — collection read helpers: list_collections / get_collection /
+subfolder_of."""
+from __future__ import annotations
+
+import tempfile
+from pathlib import Path
+
+from app import collections as collections_mod, db
+from app.config import Config
+
+
+def _db() -> Config:
+    cfg = Config(
+        gitea_url="x", gitea_bot_user="x", gitea_bot_token="x", gitea_org="x",
+        registry_repo="registry", oauth_client_id="x",
+        oauth_client_secret="x", app_url="x", secret_key="x",
+        database_path=Path(tempfile.mkdtemp(prefix="colhelp-")) / "t.db",
+        owner_gitea_login="x", webhook_secret="x",
+    )
+    db.run_migrations(cfg)
+    if db._CONN is not None:
+        db._CONN.close()
+        db._CONN = None
+    db.init(cfg)
+    return cfg
+
+
+def _seed(project_id="ohm"):
+    db.conn().execute(
+        "INSERT OR REPLACE INTO projects (id, name, content_repo, visibility, updated_at) "
+        "VALUES (?, 'Ohm', 'ohm-rfc', 'public', datetime('now'))", (project_id,))
+    for cid, sub, vis, name in [
+        ("default", "", "public", "Model"),
+        ("features", "features", "public", "Features"),
+        ("secret", "secret", "unlisted", "Secret"),
+    ]:
+        db.conn().execute(
+            "INSERT OR REPLACE INTO collections (id, project_id, type, subfolder, initial_state, "
+            "visibility, name, created_at, updated_at) VALUES (?,?, 'document', ?, "
+            "'super-draft', ?, ?, datetime('now'), datetime('now'))",
+            (cid, project_id, sub, vis, name))
+
+
+def test_list_collections_excludes_unlisted():
+    _db()
+    _seed()
+    ids = [c["id"] for c in collections_mod.list_collections("ohm", include_unlisted=False)]
+    assert ids == ["default", "features"]  # default first, then by name; 'secret' omitted
+
+
+def test_list_collections_include_unlisted():
+    _db()
+    _seed()
+    ids = {c["id"] for c in collections_mod.list_collections("ohm", include_unlisted=True)}
+    assert ids == {"default", "features", "secret"}
+
+
+def test_get_collection_and_subfolder():
+    _db()
+    _seed()
+    assert collections_mod.get_collection("features")["name"] == "Features"
+    assert collections_mod.subfolder_of("features") == "features"
+    assert collections_mod.subfolder_of("default") == ""
+    assert collections_mod.get_collection("nope") is None

backend/tests/test_collection_registry.py

@@ -0,0 +1,146 @@
+"""§22 S2 — the registry mirror reads `.collection.yaml` manifests inside each
+project's content repo and upserts a named collection per manifest. The default
+collection still flows from projects.yaml (test_registry.py)."""
+from __future__ import annotations
+
+import asyncio
+import base64
+import tempfile
+from pathlib import Path
+
+import pytest
+
+from app import db, registry
+from app.config import Config
+
+
+def _db() -> Config:
+    cfg = Config(
+        gitea_url="x", gitea_bot_user="x", gitea_bot_token="x", gitea_org="wiggleverse",
+        registry_repo="registry", oauth_client_id="x",
+        oauth_client_secret="x", app_url="x", secret_key="x",
+        database_path=Path(tempfile.mkdtemp(prefix="colreg-")) / "t.db",
+        owner_gitea_login="x", webhook_secret="x",
+    )
+    db.run_migrations(cfg)
+    if db._CONN is not None:
+        db._CONN.close()
+        db._CONN = None
+    db.init(cfg)
+    return cfg
+
+
+# --- pure parser --------------------------------------------------------------
+
+
+def test_parse_collection_manifest_minimal():
+    doc = registry.parse_collection_manifest("type: bdd\n")
+    assert doc.type == "bdd"
+    # §22.4b: bdd defaults to 'active'; visibility inherits (None == inherit).
+    assert doc.initial_state == "active"
+    assert doc.visibility is None
+    assert doc.name is None
+
+
+def test_parse_collection_manifest_full():
+    doc = registry.parse_collection_manifest(
+        "type: document\nvisibility: public\ninitial_state: active\nname: Model\n"
+    )
+    assert (doc.type, doc.visibility, doc.initial_state, doc.name) == (
+        "document", "public", "active", "Model",
+    )
+
+
+def test_parse_collection_manifest_rejects_bad_type():
+    with pytest.raises(registry.RegistryError):
+        registry.parse_collection_manifest("type: nonsense\n")
+
+
+def test_parse_collection_manifest_rejects_bad_visibility():
+    with pytest.raises(registry.RegistryError):
+        registry.parse_collection_manifest("type: bdd\nvisibility: nope\n")
+
+
+# --- mirror discovery ---------------------------------------------------------
+
+
+class _FakeGitea:
+    """Minimal Gitea stub: projects.yaml in the registry repo + a content repo
+    whose root holds a `features/` subdir carrying a `.collection.yaml`."""
+
+    def __init__(self, projects_yaml: str, repo_tree: dict[str, dict[str, str]]):
+        self._projects_yaml = projects_yaml
+        self._repo_tree = repo_tree  # {repo: {path: text}}
+
+    async def get_contents(self, org, repo, path, ref="main"):
+        if path == "projects.yaml":
+            return {"type": "file",
+                    "content": base64.b64encode(self._projects_yaml.encode()).decode(),
+                    "sha": "regsha-test"}
+        text = self._repo_tree.get(repo, {}).get(path)
+        if text is None:
+            return None
+        return {"type": "file",
+                "content": base64.b64encode(text.encode()).decode(), "sha": "c0ffee"}
+
+    async def list_dir(self, org, repo, path, ref="main"):
+        # Root listing: surface each top-level segment as a 'dir' entry.
+        prefix = (path.rstrip("/") + "/") if path else ""
+        dirs = set()
+        for p in self._repo_tree.get(repo, {}):
+            if not p.startswith(prefix):
+                continue
+            rest = p[len(prefix):]
+            if "/" in rest:
+                dirs.add(rest.split("/", 1)[0])
+        return [{"type": "dir", "name": n, "path": prefix + n} for n in sorted(dirs)]
+
+
+_PROJECTS = (
+    "deployment:\n  name: Ohm\n  tagline: t\n"
+    "projects:\n  - id: ohm\n    name: Ohm\n    type: document\n"
+    "    content_repo: ohm-rfc\n    visibility: public\n"
+)
+
+
+def test_refresh_registry_mirrors_named_collection():
+    cfg = _db()
+    gitea = _FakeGitea(
+        projects_yaml=_PROJECTS,
+        repo_tree={"ohm-rfc": {"features/.collection.yaml": "type: bdd\nname: Features\n"}},
+    )
+    asyncio.run(registry.refresh_registry(cfg, gitea))
+    row = db.conn().execute(
+        "SELECT type, subfolder, name, project_id, visibility FROM collections WHERE id='features'"
+    ).fetchone()
+    assert row is not None
+    assert (row["type"], row["subfolder"], row["project_id"]) == ("bdd", "features", "ohm")
+    assert row["name"] == "Features"
+    # visibility inherits the project's (public) when the manifest omits it.
+    assert row["visibility"] == "public"
+
+
+def test_refresh_registry_leaves_default_collection_intact():
+    cfg = _db()
+    gitea = _FakeGitea(
+        projects_yaml=_PROJECTS,
+        repo_tree={"ohm-rfc": {"features/.collection.yaml": "type: bdd\n"}},
+    )
+    asyncio.run(registry.refresh_registry(cfg, gitea))
+    # The default collection (from projects.yaml) and the named one coexist.
+    ids = {r["id"] for r in db.conn().execute("SELECT id FROM collections")}
+    assert {"default", "features"} <= ids
+
+
+def test_refresh_registry_immutable_type_on_named_collection():
+    cfg = _db()
+    gitea = _FakeGitea(
+        projects_yaml=_PROJECTS,
+        repo_tree={"ohm-rfc": {"features/.collection.yaml": "type: bdd\n"}},
+    )
+    asyncio.run(registry.refresh_registry(cfg, gitea))
+    # A later manifest that flips the type is refused (§22.4a immutable type).
+    gitea._repo_tree["ohm-rfc"]["features/.collection.yaml"] = "type: document\n"
+    asyncio.run(registry.refresh_registry(cfg, gitea))
+    t = db.conn().execute("SELECT type FROM collections WHERE id='features'").fetchone()["type"]
+    assert t == "bdd"

backend/tests/test_collection_scoped_serve.py

@@ -0,0 +1,159 @@
+"""§22 S2 — collection-grained corpus mirror + collection-scoped serve/propose.
+
+The mirror test drives cache.refresh_meta_repo against an in-memory content repo
+holding entries under both the default `rfcs/` and a named collection's
+`features/rfcs/`, and asserts cached_rfcs is keyed by the right collection_id."""
+from __future__ import annotations
+
+import asyncio
+import tempfile
+from pathlib import Path
+
+from app import cache, db
+from app.config import Config
+
+
+def _db() -> Config:
+    cfg = Config(
+        gitea_url="x", gitea_bot_user="x", gitea_bot_token="x", gitea_org="wiggleverse",
+        registry_repo="registry", oauth_client_id="x",
+        oauth_client_secret="x", app_url="x", secret_key="x",
+        database_path=Path(tempfile.mkdtemp(prefix="colserve-")) / "t.db",
+        owner_gitea_login="x", webhook_secret="x",
+    )
+    db.run_migrations(cfg)
+    if db._CONN is not None:
+        db._CONN.close()
+        db._CONN = None
+    db.init(cfg)
+    return cfg
+
+
+class _CorpusGitea:
+    """A content repo modelled as a flat {path: text} map, listing files under a
+    directory prefix and reading them back."""
+
+    def __init__(self, tree: dict[str, str]):
+        self._tree = tree
+
+    async def list_dir(self, org, repo, path, ref="main"):
+        out = []
+        prefix = (path.rstrip("/") + "/") if path else ""
+        for p in self._tree:
+            if p.startswith(prefix) and "/" not in p[len(prefix):]:
+                out.append({"type": "file", "name": p.split("/")[-1], "path": p})
+        return out
+
+    async def read_file(self, org, repo, path, ref="main"):
+        t = self._tree.get(path)
+        return (t, "sha-" + path) if t is not None else None
+
+
+def _entry_md(slug, title):
+    return f"---\nslug: {slug}\ntitle: {title}\nstate: active\n---\nbody\n"
+
+
+def _seed_project_with_two_collections():
+    db.conn().execute(
+        "INSERT OR REPLACE INTO projects (id, name, content_repo, visibility, updated_at) "
+        "VALUES ('ohm','Ohm','ohm-rfc','public', datetime('now'))")
+    for cid, sub in [("default", ""), ("features", "features")]:
+        db.conn().execute(
+            "INSERT OR REPLACE INTO collections (id, project_id, type, subfolder, initial_state, "
+            "visibility, created_at, updated_at) VALUES (?, 'ohm','document',?, "
+            "'super-draft','public', datetime('now'), datetime('now'))", (cid, sub))
+
+
+def test_mirror_keys_entries_by_collection():
+    cfg = _db()
+    _seed_project_with_two_collections()
+    gitea = _CorpusGitea({
+        "rfcs/a.md": _entry_md("a", "Default A"),
+        "features/rfcs/b.md": _entry_md("b", "Feature B"),
+    })
+    asyncio.run(cache.refresh_meta_repo(cfg, gitea))
+    got = {(r["collection_id"], r["slug"]) for r in
+           db.conn().execute("SELECT collection_id, slug FROM cached_rfcs")}
+    assert got == {("default", "a"), ("features", "b")}
+
+
+# --- collection-scoped serve + propose (full app) -----------------------------
+
+from fastapi.testclient import TestClient  # noqa: E402
+from test_propose_vertical import (  # noqa: E402,F401
+    app_with_fake_gitea, tmp_env, provision_user_row, sign_in_as,
+)
+
+
+def _add_features_collection(content_repo="meta"):
+    """Add a named 'features' collection (subfolder 'features') under the seeded
+    default project, plus a single entry under features/rfcs/ in the db cache."""
+    db.conn().execute(
+        "INSERT OR REPLACE INTO collections (id, project_id, type, subfolder, "
+        "initial_state, visibility, name, created_at, updated_at) VALUES "
+        "('features','default','document','features','super-draft','public','Features', "
+        "datetime('now'), datetime('now'))")
+
+
+def test_scoped_list_returns_only_that_collection(app_with_fake_gitea):
+    app, fake = app_with_fake_gitea
+    with TestClient(app) as client:
+        _add_features_collection()
+        # Seed one entry under each collection's rfcs dir + mirror them in.
+        fake.files[("wiggleverse", "meta", "main", "rfcs/a.md")] = {
+            "content": _entry_md("a", "Default A"), "sha": "sa"}
+        fake.files[("wiggleverse", "meta", "main", "features/rfcs/b.md")] = {
+            "content": _entry_md("b", "Feature B"), "sha": "sb"}
+        from app import cache as cache_mod, gitea as gitea_mod
+        from app.config import load_config
+        cfg = load_config()
+        asyncio.run(cache_mod.refresh_meta_repo(cfg, gitea_mod.Gitea(cfg)))
+
+        r = client.get("/api/projects/default/collections/features/rfcs")
+        assert r.status_code == 200, r.text
+        assert [i["slug"] for i in r.json()["items"]] == ["b"]
+        # The default collection still serves only its own entry.
+        r2 = client.get("/api/projects/default/collections/default/rfcs")
+        assert [i["slug"] for i in r2.json()["items"]] == ["a"]
+
+
+def test_scoped_propose_writes_into_collection_subfolder(app_with_fake_gitea):
+    app, fake = app_with_fake_gitea
+    with TestClient(app) as client:
+        _add_features_collection()
+        provision_user_row(user_id=3, login="alice", role="contributor")
+        sign_in_as(client, user_id=3, gitea_login="alice", display_name="Alice",
+                   role="contributor", email="alice@test")
+        r = client.post(
+            "/api/projects/default/collections/features/rfcs/propose",
+            json={"title": "New B", "slug": "newb", "pitch": "x", "tags": []})
+        assert r.status_code == 200, r.text
+        # The bot wrote the entry under features/rfcs/, not rfcs/.
+        keys = {(k[1], k[3]) for k in fake.files
+                if k[1] == "meta" and k[3].endswith("newb.md")}
+        assert ("meta", "features/rfcs/newb.md") in keys
+
+
+def test_scoped_routes_404_for_collection_outside_project(app_with_fake_gitea):
+    app, _ = app_with_fake_gitea
+    with TestClient(app) as client:
+        r = client.get("/api/projects/default/collections/nope/rfcs")
+        assert r.status_code == 404
+
+
+def test_s2_anonymous_empty_public_collection(app_with_fake_gitea):
+    """C3.6 (@S2): a public collection with no entries; an anonymous visitor
+    lands on its catalog → an empty catalog (200, no items), and the propose
+    action is not available to them (the propose route rejects anonymous)."""
+    app, _ = app_with_fake_gitea
+    with TestClient(app) as client:
+        _add_features_collection()  # public, no entries
+        # Anonymous (no session cookie) reads the empty catalog — 200, [].
+        r = client.get("/api/projects/default/collections/features/rfcs")
+        assert r.status_code == 200, r.text
+        assert r.json()["items"] == []
+        # No propose action for an anonymous visitor.
+        r2 = client.post(
+            "/api/projects/default/collections/features/rfcs/propose",
+            json={"title": "X", "slug": "x", "pitch": "p", "tags": []})
+        assert r2.status_code == 401

backend/tests/test_propose_vertical.py

@@ -90,6 +90,28 @@ class FakeGitea:
         self._commit_counter += 1
         return f"sha{self._commit_counter:04d}"
 
+    def _dir_listing(self, owner, repo, ref, dirpath):
+        """Children directly under `dirpath` on (owner, repo, ref): files as
+        `type: file` and immediate subdirectories as `type: dir` (the shape real
+        Gitea returns for a contents listing)."""
+        prefix = (dirpath.rstrip("/") + "/") if dirpath else ""
+        files: dict[str, dict] = {}
+        dirs: set[str] = set()
+        for (o, r, br, p), data in self.files.items():
+            if (o, r, br) != (owner, repo, ref) or not p.startswith(prefix):
+                continue
+            rest = p[len(prefix):]
+            if "/" in rest:
+                dirs.add(rest.split("/", 1)[0])
+            elif rest:
+                files[p] = data
+        children = [{"name": n, "path": prefix + n, "type": "dir"} for n in sorted(dirs)]
+        children += [
+            {"name": p.rsplit("/", 1)[-1], "path": p, "type": "file", "sha": d["sha"]}
+            for p, d in sorted(files.items())
+        ]
+        return children
+
     def _enrich_pr(self, owner: str, repo: str, pr: dict) -> dict:
         """Return the PR with mergeability fields filled in.
 
@@ -227,6 +249,16 @@ class FakeGitea:
             }
             return httpx.Response(201, json={"name": new})
 
+        # GET /repos/{owner}/{repo}/contents (root listing, empty path). §22 S2:
+        # the registry mirror walks the content-repo root for collection
+        # subfolders, so the simulator models a root directory listing that
+        # surfaces both file and `dir` children.
+        m_root = re.fullmatch(r"/repos/([^/]+)/([^/]+)/contents/?", path)
+        if method == "GET" and m_root:
+            owner, repo = m_root.groups()
+            ref = request.url.params.get("ref", "main")
+            return httpx.Response(200, json=self._dir_listing(owner, repo, ref, ""))
+
         # GET /repos/{owner}/{repo}/contents/{path}?ref=...
         m = re.fullmatch(r"/repos/([^/]+)/([^/]+)/contents/(.+)", path)
         if method == "GET" and m:
@@ -242,17 +274,8 @@ class FakeGitea:
                     "sha": f["sha"],
                     "content": base64.b64encode(f["content"].encode()).decode(),
                 })
-            # Directory listing
-            prefix = fpath.rstrip("/") + "/"
-            children = []
-            for (o, r, br, p), data in self.files.items():
-                if (o, r, br) == (owner, repo, ref) and p.startswith(prefix) and "/" not in p[len(prefix):]:
-                    children.append({
-                        "name": p.rsplit("/", 1)[-1],
-                        "path": p,
-                        "type": "file",
-                        "sha": data["sha"],
-                    })
+            # Directory listing — both file and subdir children.
+            children = self._dir_listing(owner, repo, ref, fpath)
             if children:
                 return httpx.Response(200, json=children)
             return httpx.Response(404, json={"message": "not found"})

docs/design/2026-06-05-three-tier-projects-collections.md

@@ -549,7 +549,8 @@ means the deployment runs and either gains a capability or provably loses none
   exactly as before, now with a real collection layer and one extra path segment.
   **Completes:** `@S1` (the single-collection / single-project redirect skips).
 
-- **S2 — Create & navigate a second collection.** Teach the registry mirror to
+- **S2 — Create & navigate a second collection.** *(Shipped v0.41.0.)* Teach the
+  registry mirror to
   read `.collection.yaml`; add the bot-commit-wrapped **create-collection**
   endpoint (authorized by existing deployment owner/admin for now — the scoped
   role surface lands in S3); the project collection-directory at `/p/<project>/`;

frontend/package.json

@@ -1,7 +1,7 @@
 {
   "name": "rfc-app-frontend",
   "private": true,
-  "version": "0.40.0",
+  "version": "0.41.0",
   "type": "module",
   "scripts": {
     "dev": "vite",

frontend/src/App.jsx

@@ -15,6 +15,7 @@ import RFCView from './components/RFCView.jsx'
 import PRView from './components/PRView.jsx'
 import ProposalView from './components/ProposalView.jsx'
 import ProposeModal from './components/ProposeModal.jsx'
+import CollectionDirectory from './components/CollectionDirectory.jsx'
 import ContributeRequestForm from './components/ContributeRequestForm.jsx'
 import Landing from './components/Landing.jsx'
 import Login from './components/Login.jsx'
@@ -66,6 +67,10 @@ export default function App() {
   // right project. Falls back to the deployment default off a project route.
   const _projMatch = location.pathname.match(/^\/p\/([^/]+)/)
   const currentProjectId = (_projMatch && _projMatch[1]) || deployment.defaultProjectId
+  // §22 S2 — the collection the viewer is currently in (from the /c/<cid>/ URL
+  // segment), so a propose targets that collection. Falls back to the default.
+  const _colMatch = location.pathname.match(/^\/p\/[^/]+\/c\/([^/]+)/)
+  const currentCollectionId = (_colMatch && _colMatch[1]) || DEFAULT_COLLECTION
   // #28 Parts 2–3: the LinkedText create/contribute affordances route via
   // query params so they need no prop-threading from deep in a comment
   // list. `?propose=<term>` opens the propose modal pre-filled;
@@ -360,9 +365,10 @@ export default function App() {
               />
               <main className="main-pane">
                 <Routes>
-                  {/* §22 three-tier (C3.7): the project landing redirects into
-                      its sole/default collection (S1: the `default` one). */}
-                  <Route path="" element={<DefaultCollectionRedirect />} />
+                  {/* §22 S2: the project landing is the collection directory —
+                      it lists collections, or (C3.7/C3.8) redirects into the
+                      sole visible collection when there is exactly one. */}
+                  <Route path="" element={<CollectionDirectoryRoute />} />
                   {/* Backcompat: the shipped v0.35.0 corpus URLs without a
                       /c/<collection>/ segment redirect into the default
                       collection, so old bookmarks keep working. */}
@@ -389,12 +395,13 @@ export default function App() {
           viewer={viewer}
           initialTitle={proposeParam || ''}
           projectId={currentProjectId}
+          collectionId={currentCollectionId}
           onClose={() => { setProposeOpen(false); clearParams('propose') }}
           onSubmitted={({ pr_number }) => {
             setProposeOpen(false)
             clearParams('propose')
             setCatalogVersion(v => v + 1)
-            navigate(proposalPath(currentProjectId, pr_number))
+            navigate(proposalPath(currentProjectId, pr_number, currentCollectionId))
           }}
         />
       )}
@@ -414,12 +421,12 @@ export default function App() {
   )
 }
 
-// §22 three-tier — corpus redirects mounted under /p/:projectId/*.
-// C3.7: the project landing skips the (single-collection) directory and lands in
-// the project's default collection.
-function DefaultCollectionRedirect() {
+// §22 S2 — the project landing at /p/:projectId/ is the collection directory.
+// A tiny wrapper reads the route's projectId and hands it to CollectionDirectory
+// (which lists collections, or redirects into the sole one — C3.7/C3.8).
+function CollectionDirectoryRoute() {
   const { projectId } = useParams()
-  return <Navigate to={`/p/${projectId}/c/${DEFAULT_COLLECTION}/`} replace />
+  return <CollectionDirectory projectId={projectId} />
 }
 
 // Backcompat for the shipped v0.35.0 corpus URLs that lacked the

frontend/src/api.collections.test.js

@@ -0,0 +1,48 @@
+// §22 S2 — the API client builds collection-scoped URLs when a collection id is
+// supplied, and falls back to the project/default-collection paths otherwise.
+import { describe, it, expect, vi, afterEach } from 'vitest'
+import { listRFCs, getRFC, proposeRFC, listCollections } from './api.js'
+
+function mockFetch() {
+  const fn = vi.fn(async () => ({
+    ok: true,
+    status: 200,
+    json: async () => ({ items: [] }),
+  }))
+  global.fetch = fn
+  return fn
+}
+
+afterEach(() => { vi.restoreAllMocks() })
+
+describe('collection-scoped api URLs', () => {
+  it('listRFCs scopes to a collection when given one', async () => {
+    const f = mockFetch()
+    await listRFCs('ohm', 'features')
+    expect(f).toHaveBeenCalledWith('/api/projects/ohm/collections/features/rfcs')
+  })
+
+  it('listRFCs falls back to the project default path without a collection', async () => {
+    const f = mockFetch()
+    await listRFCs('ohm')
+    expect(f).toHaveBeenCalledWith('/api/projects/ohm/rfcs')
+  })
+
+  it('getRFC scopes to a collection when given one', async () => {
+    const f = mockFetch()
+    await getRFC('ohm', 'login', 'features')
+    expect(f).toHaveBeenCalledWith('/api/projects/ohm/collections/features/rfcs/login')
+  })
+
+  it('proposeRFC targets the collection-scoped propose route', async () => {
+    const f = mockFetch()
+    await proposeRFC('ohm', { title: 'T', slug: 's', pitch: 'p', tags: [], collectionId: 'features' })
+    expect(f.mock.calls[0][0]).toBe('/api/projects/ohm/collections/features/rfcs/propose')
+  })
+
+  it('listCollections hits the project collections route', async () => {
+    const f = mockFetch()
+    await listCollections('ohm')
+    expect(f).toHaveBeenCalledWith('/api/projects/ohm/collections')
+  })
+})

frontend/src/api.js

@@ -182,22 +182,50 @@ export async function getProject(projectId) {
   return jsonOrThrow(await fetch(`/api/projects/${projectId}`))
 }
 
-// §22.4 (Plan B): per-project serving. Given a projectId, read the
-// project-scoped routes so a non-default project's corpus renders; without
-// one, fall back to the default-project compat path.
-export async function listRFCs(projectId) {
+// §22.4 (Plan B) / §22 S2: per-collection serving. With a projectId + a
+// collectionId, read the collection-scoped routes; with only a projectId, the
+// project default-collection compat path; with neither, the unscoped path.
+export async function listRFCs(projectId, collectionId) {
+  if (projectId && collectionId) {
+    return jsonOrThrow(await fetch(`/api/projects/${projectId}/collections/${collectionId}/rfcs`))
+  }
   const url = projectId ? `/api/projects/${projectId}/rfcs` : '/api/rfcs'
   return jsonOrThrow(await fetch(url))
 }
 
-export async function getRFC(projectId, slug) {
+export async function getRFC(projectId, slug, collectionId) {
   // Back-compat: getRFC(slug) (one arg) still hits the unscoped default path.
   if (slug === undefined) {
     return jsonOrThrow(await fetch(`/api/rfcs/${projectId}`))
   }
+  if (collectionId) {
+    return jsonOrThrow(await fetch(`/api/projects/${projectId}/collections/${collectionId}/rfcs/${slug}`))
+  }
   return jsonOrThrow(await fetch(`/api/projects/${projectId}/rfcs/${slug}`))
 }
 
+// §22 S2: the collections of a project (for the /p/<project>/ directory).
+export async function listCollections(projectId) {
+  return jsonOrThrow(await fetch(`/api/projects/${projectId}/collections`))
+}
+
+// §22 S2: create-collection (deployment owner/admin). The backend commits a
+// .collection.yaml and re-mirrors the registry, returning the new collection.
+export async function createCollection(projectId, { collectionId, type, name, visibility, initialState }) {
+  const res = await fetch(`/api/projects/${projectId}/collections`, {
+    method: 'POST',
+    headers: { 'Content-Type': 'application/json' },
+    body: JSON.stringify({
+      collection_id: collectionId,
+      type,
+      name: name || null,
+      visibility: visibility || null,
+      initial_state: initialState || null,
+    }),
+  })
+  return jsonOrThrow(res)
+}
+
 export async function listProposals(projectId) {
   const url = projectId ? `/api/projects/${projectId}/proposals` : '/api/proposals'
   return jsonOrThrow(await fetch(url))
@@ -209,8 +237,10 @@ export async function getProposal(prNumber) {
 
 // §22.4 (Plan B write): propose into a specific project when projectId is
 // given; else the default-project compat path.
-export async function proposeRFC(projectId, { title, slug, pitch, tags, proposedUseCase }) {
-  const url = projectId ? `/api/projects/${projectId}/rfcs/propose` : '/api/rfcs/propose'
+export async function proposeRFC(projectId, { title, slug, pitch, tags, proposedUseCase, collectionId }) {
+  const url = (projectId && collectionId)
+    ? `/api/projects/${projectId}/collections/${collectionId}/rfcs/propose`
+    : (projectId ? `/api/projects/${projectId}/rfcs/propose` : '/api/rfcs/propose')
   const res = await fetch(url, {
     method: 'POST',
     headers: { 'Content-Type': 'application/json' },

frontend/src/components/Catalog.jsx

@@ -9,7 +9,7 @@
 import { useEffect, useMemo, useState } from 'react'
 import { useParams, Link } from 'react-router-dom'
 import { listRFCs, listProposals } from '../api'
-import { entryPath, proposalPath, useProjectId } from '../lib/entryPaths'
+import { entryPath, proposalPath, useProjectId, useCollectionId } from '../lib/entryPaths'
 
 const STATE_CHIPS = [
   { id: 'super-draft', label: 'Super-draft' },
@@ -32,11 +32,14 @@ export default function Catalog({ viewer, onProposeRFC, version }) {
   const [pendingOpen, setPendingOpen] = useState(true)
   const { slug, prNumber } = useParams()
   const pid = useProjectId()
+  // §22 S2: the catalog is scoped to the active collection (the `/c/:cid/`
+  // route segment, else the project's default collection).
+  const cid = useCollectionId()
 
   useEffect(() => {
-    listRFCs(pid).then(d => setRfcs(d.items)).catch(() => setRfcs([]))
+    listRFCs(pid, cid).then(d => setRfcs(d.items)).catch(() => setRfcs([]))
     listProposals(pid).then(d => setProposals(d.items)).catch(() => setProposals([]))
-  }, [version, pid])
+  }, [version, pid, cid])
 
   const filtered = useMemo(() => {
     const needle = search.trim().toLowerCase()
@@ -105,7 +108,7 @@ export default function Catalog({ viewer, onProposeRFC, version }) {
             return (
               <Link
                 key={r.slug}
-                to={entryPath(pid, r.slug)}
+                to={entryPath(pid, r.slug, cid)}
                 className={`catalog-row ${isActive ? 'active' : ''} ${isSuper ? 'is-super' : ''}`}
               >
                 <div className="row-top">
@@ -133,7 +136,7 @@ export default function Catalog({ viewer, onProposeRFC, version }) {
             {proposals.map(p => (
               <Link
                 key={p.pr_number}
-                to={proposalPath(pid, p.pr_number)}
+                to={proposalPath(pid, p.pr_number, cid)}
                 className={`pending-row ${String(prNumber) === String(p.pr_number) ? 'active' : ''}`}
               >
                 <div>{p.title.replace(/^Propose:\s*/, '')}</div>

frontend/src/components/CollectionDirectory.jsx

@@ -0,0 +1,51 @@
+// §22 S2 — the project collection directory at `/p/<project>/`. Lists the
+// project's caller-visible collections as cards linking into each collection's
+// `/p/<project>/c/<collection>/` home. When exactly one collection is visible
+// the directory is skipped and we redirect straight into it (the S1 C3.7/C3.8
+// single-collection UX, preserved). The role-keyed "Create your first
+// collection" empty state is S4; S2 shows a minimal note when there are none.
+import { useEffect, useState } from 'react'
+import { Link, Navigate } from 'react-router-dom'
+import { listCollections } from '../api'
+import { collectionHome } from '../lib/entryPaths'
+import { entryNoun } from './ProjectLayout.jsx'
+
+export default function CollectionDirectory({ projectId }) {
+  const [cols, setCols] = useState(null)
+  useEffect(() => {
+    let live = true
+    listCollections(projectId)
+      .then(d => { if (live) setCols(d.items) })
+      .catch(() => { if (live) setCols([]) })
+    return () => { live = false }
+  }, [projectId])
+
+  if (cols === null) {
+    return <main className="chrome-pane"><div className="boot">Loading…</div></main>
+  }
+  // C3.7/C3.8: a single visible collection skips the directory.
+  if (cols.length === 1) {
+    return <Navigate to={collectionHome(projectId, cols[0].id)} replace />
+  }
+  return (
+    <main className="chrome-pane">
+      <div className="directory">
+        <h1>Collections</h1>
+        {cols.length === 0 ? (
+          <p className="directory-tagline">No collections yet.</p>
+        ) : (
+          <ul className="directory-list">
+            {cols.map(c => (
+              <li key={c.id} className="directory-card">
+                <Link to={collectionHome(projectId, c.id)}>
+                  <span className="directory-card-name">{c.name || c.id}</span>
+                  <span className="directory-card-type">{entryNoun(c.type)}s</span>
+                </Link>
+              </li>
+            ))}
+          </ul>
+        )}
+      </div>
+    </main>
+  )
+}

frontend/src/components/CollectionDirectory.test.jsx

@@ -0,0 +1,48 @@
+import React from 'react'
+import { describe, it, expect, vi, beforeEach } from 'vitest'
+import { render, screen, waitFor } from '@testing-library/react'
+import { MemoryRouter, Routes, Route } from 'react-router-dom'
+
+let mockItems = []
+vi.mock('../api', () => ({
+  listCollections: vi.fn(async () => ({ items: mockItems })),
+}))
+import CollectionDirectory from './CollectionDirectory.jsx'
+
+beforeEach(() => { mockItems = [] })
+
+function renderDir(items) {
+  mockItems = items
+  return render(
+    <MemoryRouter initialEntries={["/p/ohm/"]}>
+      <Routes>
+        <Route path="/p/:projectId/*" element={<CollectionDirectory projectId="ohm" />} />
+        <Route path="/p/:projectId/c/:collectionId/*" element={<div>collection home</div>} />
+      </Routes>
+    </MemoryRouter>,
+  )
+}
+
+describe('CollectionDirectory', () => {
+  it('lists a card per collection with the type-driven noun + link when 2+', async () => {
+    renderDir([
+      { id: 'default', name: 'Model', type: 'document' },
+      { id: 'features', name: 'Scenarios', type: 'bdd' },
+    ])
+    await waitFor(() => expect(screen.getByText('Scenarios')).toBeInTheDocument())
+    expect(screen.getByText('Model').closest('a')).toHaveAttribute('href', '/p/ohm/c/default/')
+    expect(screen.getByText('Scenarios').closest('a')).toHaveAttribute('href', '/p/ohm/c/features/')
+    expect(screen.getByText('RFCs')).toBeInTheDocument()       // document → RFCs
+    expect(screen.getByText('Features')).toBeInTheDocument()   // bdd → Features (type noun)
+  })
+
+  it('redirects into the sole collection when exactly one is visible', async () => {
+    renderDir([{ id: 'default', name: 'Model', type: 'document' }])
+    await waitFor(() => expect(screen.getByText('collection home')).toBeInTheDocument())
+  })
+
+  it('shows a minimal empty note when there are no collections', async () => {
+    renderDir([])
+    await waitFor(() => expect(screen.getByText('No collections yet.')).toBeInTheDocument())
+  })
+})

frontend/src/components/ProposeModal.jsx

@@ -28,7 +28,7 @@ function slugify(title) {
     .replace(/^-+|-+$/g, '')
 }
 
-export default function ProposeModal({ viewer, onClose, onSubmitted, initialTitle = '', projectId }) {
+export default function ProposeModal({ viewer, onClose, onSubmitted, initialTitle = '', projectId, collectionId }) {
   // #28 Part 2: a "create RFC for '<term>'" affordance pre-fills the title
   // (App passes the `?propose=<term>` value here); the slug derives from it
   // via the same effect that drives manual typing.
@@ -98,6 +98,7 @@ export default function ProposeModal({ viewer, onClose, onSubmitted, initialTitl
         pitch: pitch.trim(),
         tags,
         proposedUseCase: useCase.trim() || null,
+        collectionId,
       })
       // v0.15.0 — analytics: fire on the §9.1 propose-RFC submit.
       // Slug is a stable, low-cardinality identifier (kebab-case

frontend/src/lib/entryPaths.js

@@ -4,6 +4,7 @@
 // project-scoped, so the builders emit the default collection segment; the
 // collection-aware link layer (named collections) lands in S2. Components build
 // links via these helpers so that flip happens in one place.
+import { useParams } from 'react-router-dom'
 import { useProject } from '../components/ProjectLayout.jsx'
 import { useDeployment } from '../context/DeploymentProvider'
 
@@ -37,3 +38,10 @@ export function useProjectId() {
   const { defaultProjectId } = useDeployment()
   return (ctx && ctx.projectId) || defaultProjectId
 }
+
+// §22 S2 — the collection id a component should scope to: the `/c/:collectionId/`
+// route segment when present, else the project's default collection.
+export function useCollectionId() {
+  const { collectionId } = useParams()
+  return collectionId || DEFAULT_COLLECTION
+}